yeah these will lock it down solid, but the in cabin noise will increase by a fair bit. when i had to do the same in my 32 i went for taking the car off the roar for a week, i had another to drive, worked on it a little bit each arvo after work and changed the bushes for a set of Noltec ones.
i dont know if you can still get noltec bushes, you'll have to check, but its your only real other option. the in cabin noise only increased by a little bit with them, nowhere near as much as a set of the solid mount ones though.
http://www.skylinesaustralia.com/forums/R3...20&start=20